Shawn Mendes knows how to speak to young people.
This fresh-faced singer from suburban Toronto first built an audience through the video-sharing app Vine, where three years ago he started posting bite-size acoustic covers of pop hits by stars like Ed Sheeran and Beyoncé.
By 2014, Mendes had signed a major-label deal with Island Records, and last year, he made it to No. 4 on Billboard's Hot 100 with "Stitches," a bouncy breakup song that's been streamed more than a billion times on YouTube and Spotify.
On a recent weekday morning, though, it wasn't his teenage social-media followers Mendes was communicating with but someone a bit more mature: Larry King, the octogenarian broadcasting legend who'd invited the singer to appear on his old-fashioned talk show.
"He called me Frank Sinatra!" Mendes, 18, later exclaimed. "That's amazing."
Winning over the 80-and-above demographic may not top Mendes' list of priorities, but with his surprising new album, "Illuminate," he's definitely looking to connect with listeners beyond his youthful core.
Due Sept. 23, the record trades the peppy energy that defined "Stitches" (and helped earn Mendes a gig opening for Taylor Swift) for a deeper, more introspective vibe. It's full of sparse, unhurried tunes like the delicate "Three Empty Words" and "Ruin," a bluesy ballad with strong echoes of John Mayer's "Gravity." And then there's the dramatic "Mercy," in which he describes how a lover makes him feel like she's "ripping all the skin from off my bones."
"I feel like this was my first time really writing, my first time really singing and creating," Mendes said as he sat in an office at King's Glendale studio. "I wanted to prove to the outside world there's a reason I have 13 million followers."
Given that loyal base and the Top 40 success of "Stitches," it's easy to imagine the various ways "Illuminate" might have turned out — as a shiny pop production, for instance, or a thumping, trendy foray into electronic dance music.
"Big record, lots of fans — the lane was wide open," Mendes said. He briefly entertained those ideas himself, meeting with some of the industry's most reliable hitmakers.
Yet he ended up taking a different path.
For help with material, he turned to respected songwriters including Tobias Jesso Jr., a fellow Canadian (now based in Los Angeles) known for his cult-fave solo album "Goon" and for co-writing "When We Were Young" with Adele.
And to produce the album, Mendes enlisted one of Sheeran's closest collaborators, Jake Gosling, who oversaw the British artist's Grammy-winning "Thinking Out Loud."
Recalling the demos Mendes sent him, Gosling said he could hear "an honesty and a maturity" that made it clear the singer had decided by then what he wanted to do with the record.
"The growing-up-ness was really coming through," the producer said, "not only in what he was singing about but in the way he was delivering the songs."
To capture the intimacy of the music, Gosling and Mendes cloistered themselves in a recording studio in upstate New York — a stark contrast from Mendes' experience on his debut full-length, last year's "Handwritten," which he pieced together in a rush to capitalize on his exploding Internet fame.
"I tried my best, and that's what I came up with," he said, referring to the earlier record with a note of apology in his voice.
Last year was a grind, he freely acknowledges, and you can sense the effect that nonstop hustling had on him. It's there in the way he'll start answering a question before he's heard the whole thing, or in his eagerness to climb inside a waiting SUV before he's spotted by any 14-year-old girls who might be walking by (even on a quiet Glendale street).
That's partly why the idea of working in seclusion appealed to him, he said. Tuning out the retweets and the meet-and-greets allowed him to concentrate on his singing, which by his estimate is what consumes 90% of his thoughts every day.
"Right now, I'm thinking about how underneath my tongue, there's a little bit of tension, and I'm worried it's gonna pull from my high range tomorrow," he said, massaging his throat. Asked if he was expected to sing the next day, he shook his head. "No, but I just don't want it to," he said. "I'm telling you, it's obsessive."
Mendes, who's scheduled to perform Sept. 27 at the Grammy Museum and will tour arenas including Staples Center next summer, shows off that attention to his vocals throughout "Illuminate," in the creamy falsetto he finds in "Don't Be a Fool" and the newly ragged edges he explores in "Ruin."
According to Island chief David Massey, there's a "soul element that came into Shawn's voice as he grew physically." And that could be the quality that will attract older people who wrote off "Stitches" as lightweight teenybopper fare.
In fact, that's already happening, said Mendes' manager, Andrew Gertler. "When we put out 'Ruin,' I immediately got five or six texts from some of my guy friends from college," he said with a laugh. "They were like, 'Wait, this song's really good.' "
Mendes proudly recounted another such endorsement from Elton John, who brought him onstage during a recent concert at the Wiltern to sing "Tiny Dancer." But he was quick to add that, for all his growth, some things haven't changed — and likely never will.
"I picture myself now and I picture myself in 30 years and I'll probably be the same," he said. "I'll still think I'm not the greatest singer I can be."